1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a device using an ambipolar transport of an Schottky Barrier Metal-Oxide-Semiconductor Field Effect Transistor (SB-MOSFET) and a method for operating the same.
2. Description of the Related Art
A recent semiconductor fabrication technology makes it possible to fabricate a short-channel transistor of 100 nm or less. As the device is decreasing in size, many unexpected problems are rising. A reduction of gate length inevitably causes short channel effect. In order to fabricate transistor device with very small gate length, methods of suppressing short channel effect have been developed.
As size of devices becomes smaller, the devices following a simple electrical and physical law show complex characteristics caused by several new physical phenomena, which result from the short channel effect. A top-down technique has been used to reduce the existing structure of the device. However, the top-down technique has a limitation in reducing the size of the device. Accordingly, new electronic devices such as CNTs (Carbon Nano Tubes), molecular transistors, single-electron transistors and spintronic devices have been introduced.
The major problem of these new electronic devices is that they are yet in development level and it is difficult to apply the existing advanced silicon (Si) processing technologies to them. Schottky Barrier Tunnel Transistor (SBTT) or Schottky Barrier Metal-Oxide-Semiconductor Field Effect Transistor (SB-MOSFET) are introduced as a semiconductor device that can employ the existing advanced silicon processing technologies in its fabrication and overcome short channel effect of the existing MOSFET.
The SB-MOSFET is a new conceptual device that forms a Schottky barrier between source and channel and between channel and drain by a metal-silicon junction by forming source/drain of metal or metal silicide, instead of n-doped silicon layer or p-doped silicon layer.
A Schottky diode has been studied since the mid-twentieth century. A current level of the MOSFET was exhibited in the late 1990's, and a short channel SB-MOSFET having gate length of 50 nm or less has been fabricated since 2000's. Many quantum theories about operation principle of SB-MOSFET have been also studied.